Break out of those genes and go for a walk

There is most certainly a genetic predisposition for some to be overweight. However, even if you have genes that tend to cause your body to retain fat cells, you do have a weapon against the battle of the bulge – get more exercise and watch less TV.

Researchers reporting at the American Heart Association’s Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism (EPI/NPAM) meeting this week in San Diego have found that people who are physically active blunt the genetic effect of fat-increasing genes while those who remain sedentary worsen their weight gain unnecessarily.

Qibin Qi PhD, from Harvard School of Public Health, and colleagues examined data from the Nurses’ Health Study (7,740 women) and the Health Professionals Follow-up Study (4,564 men). The team calculated the participants’ genetic predisposition score based on whether or not they had any of the 32 established genetic variants that make someone more likely to have a higher body mass index (BMI).

Previous studies find that the more gene variants a person has, the more likely they are to be obese. A person at the upper end of the scale carries about 15 to 25 more pounds on average than a person who has fewer, even if they are the same height.

Those walking at least one-hour (briskly) per day had an average reduction of 0.06-0.08 kg/m2 – almost a full point on the BMI scale. That may not seem like much, but it adds up to significant health benefits. It can also help financially – one study found that each one-point decrease in BMI adds up to over $200 in savings from medical and pharmaceutical costs over the course of a year.

Advertisement

Weight loss was mainly found to be a decrease in girth, or waist circumference. Excess weight in the abdomen is substantially more risky than weight carried around the hips and thighs. An “apple” shape increased the chance of chronic health conditions such as heart disease and diabetes.

On the other side of the spectrum, for those who remained sedentary – watching TV for two hours per day – the average increase in BMI was 0.03 kg/m2 – or about 25%. But Dr. Qi notes that Americans tend to watch an average of between four and six hours of TV each day, which translates into a 50% increase in weight status beyond what the genetic predisposition would have one gain.

"We cannot change genes, but we can do something to change the influence of genes, by doing some exercise and by reducing our sedentary behavior, primarily by watching television less," said Dr. Qi.

Cant’ find time to exercise? At least get up and move around the house instead of sitting in front of the tube. In the study, even those participants who simply reduced their TV watching to less than one hour per week saw positive benefits.